Leukocyte trafficking into lymphoid tissues or sites of infection or injury is regulated by the coordinated expression of adhesion and signaling molecules [1, 2]. Binding of selecfins to glycoconjugate ligands mediates tethering and rolling on vascular surfaces. Binding of leukocyte integrins to Ig-like proteins slows rolling, promotes firm adhesion, and directs migration. Cytokines, thrombin, histamine, and other mediators inifiate leukocyte recruitment by stimulafing endothelial cells to express adhesion molecules and chemokines. Rolling leukocytes receive signals from engagement of selecfin ligands and chemokines that cause integrin-dependent deceleration, arrest, and migration. Combinatorial diversity of adhesion and signaling molecules controls the number and type of leukocytes recruited to a particular tissue, as well as the duration of the response. Dysregulated expression of these molecules contributes to tissue injury in inflammatory diseases.